Busbar Sizing Calculator

Size busbars for continuous current and short circuit withstand.

For short circuit check

Standard Busbar Sizes

Size (in) Area (in²) Cu Amps Al Amps

Busbar Design Guidelines

Current Density Limits

  • Copper: 1000-1500 A/in² (enclosed)
  • Copper: 1200-1800 A/in² (open air)
  • Aluminum: 600-1000 A/in² (enclosed)
  • Aluminum: 800-1200 A/in² (open air)

Installation Factors

  • Vertical mounting: 15-20% higher ampacity
  • Spacing: 1x bar thickness minimum
  • Multiple bars: Derate 80% per added bar
  • Enclosed: Derate 20-30% from open air